Food resource competition and habitat segregation motivate agonistic interactions among coral reef fishes. The present study analyses the relationships of agonistic encounters according to trophic guilds and life phases of fishes of the genus Haemulon in Northeastern Brazil. The individuals of this genus display the highest aggressiveness towards invertebrate feeders (90.1{%} of total percentage) and carnivores (6.4{%}), the two trophic guilds with which food preferences overlap. Meanwhile, they were attacked more by territorial herbivores from the genus Stegastes, 76.2{%} of total percentage (e.g. S. fuscus and S. variabilis). Adults performed more agonistic interactions than juveniles (Z = 2.45; p < 0.05), probably in relation with their larger body size and more solitary habits.